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Does anyone else on HN practice the multiply by 3 formula for estimates? I don't recall where I've come across it online first, but it has worked very reliably
by mhitza 4y ago
Does anyone else on HN practice the multiply by 3 formula for estimates? I don't recall where I've come across it online first, but it has worked very reliably for me in the last 3+ years.
- lotophage 4y agoAbsolutely. I find it far more accurate and when it's not, it's better to underpromise and overdeliver than to overpromise and underdeliver.
- Samon 4y agoOne of my university professors advised "multiply your best-case-scenario estimate by Pi". It's still absolutely plucking numbers out of the air, but I've found it to be pretty reasonable over the last decade or so...
- unnah 4y agoUsing pi instead of 3 has the obvious advantage that your estimates are much more precise.
- bruce511 4y agoI use 4 - double and double again. But yes, I subscribe to the approach of make your best guess, then multiply by 4.
- jbay808 4y agoDepends on who I'm talking to. An estimate is not actually a number, it's a probability distribution. Few people want to hear that; they want one number to summarize it. But not everyone wants the same number. My team wants to know the mean; my manager needs to know where the cumulative distribution reaches 90%; and marketing needs to know where the cumulative distribution reaches 99%. In my experience, a developer's educated guess hits very close to the median completion time. Software task completion tends to be lognormally distributed, so to get the appropriate scaling factors, multiply that educated guess by 1.6, 5, or 10 respectively.